Portable tool



Patented Dec. 10, 1940 PORTABLE 'rooi.

Paul Van Sittert, Cleveland Heights, Ohio, assigner to The Cleveland Pneumatic Tool Company, Cleveland, Ohio, a corporation of Ohio Application August 22, 1938, Serial No. 226,071 r 8 Claims.

This invention relates broadly to machines for performing work such as riveting, stamping, punching, shearing or, pressing, but more particularly to improvements in such machines wherein variable pressure rather than impacts is applied on the work. g

One object of the invention is to produce a portable machine wherein initial pressure applied on the work is efiected by a relatively rapid movement of the tool, which movement is gradually made slower to increase the pressure applied on the work as the pressure required to perform the work increases. j

' Another object of this invention is to provide such machines with a poweractuated mechanism capable of perforating the work as well as withdrawing the tool from the work.

Another object of this invention is to produce such machines in a manner forming a simple and compact assembly which is strong and durable, andwherein the movableparts are constructed and arranged to reduce the frictional resistance between the engaging movableparts ofthe machine. 7

Other objects and features of this invention will appear more clearly fromthe following description and drawing, of which:

Fig. 1 is a longitudinal sectional view of a shearing'machine'embodying the invention, the

, section being taken in a plane indicated by line ll in Fig.2.

Fig. 2 is a cross sectional view taken in a plane indicated by line 2--2 in Fig. 1.

- Fig. 3 is a longitudinal sectional view taken in a plane indicated by line 3-4 in Fig. 1. Referring to the drawing, there is shown a fluid actuated reciprocatory motor generally designated by 8 and including a'cylinder 9 having a handle I formingan integral part thereof. Reciprocable within the cylinder ii, there is a piston ll having an integral rack [2 depending therefrom.- The lower end of the cylinder is closed by a plate l3 formed with a central opening it within which the rack l2 i's'closely fitted for free slidable movement thercthrough. The piston II is provided with an annular groove l5 accommodating an annular packing ring IS, the inner wall of which is in communication with the upper side i1.

Rotatable within the lower portion of the cylinder 9, there is a throttle valve l8 formed with an inlet port I! and an outlet port 20, the former having motive fluid admitted therein from any suitable source of supply, and the latter being in of-the piston H through small ports constant communication with the atmosphere. This throttle valve is in communication with the upper end of the cylinder it, through a passageway 2|, while the lower end of the cylinder is in communication with the throttle valve 5 through a short passageway 22.

To the cylinder 9 is secured, by any suitable v means, a housing 23 extending downwardly to form a yoke 24, which yoke detachablyv carries a tool 25 held rigidly in position by a screw 26. o Secured within the housing 23, there is a bushing 21 having a work performing plunger 28 reciprocable therein parallelly'to the rack l-2,,the lower. end of'which plunger is shaped to detachably receive a tool 29. The upper end ofthe 15 plunger 28 is shaped as a clevisto receive a roller a 30 rotatable on a cross shaft 3| carried by the plunger, which shaft has an end 32 laterally protruding beyond the plunger-for engagement with a lever 33 having one end pivotallysecured m to'the housing 23 by a pin 34, whilethe other end of the lever is capable of engagement with a step 35 formed on the end of the rack l2. Within the housing 23, there isa rib 36 forming a vertical guiding wall 31 .engag'eable by the 3d roller 30. H

Mounted within the housing 23 in toothed engagement with the rack l2, there is a gear 38, secured on a shaft 39 by a key 40, which shaft has one end journaled within a'bushing l l car- 30 ried by the housing 23, while the other endof the shaft is journaled within a similar bushing 42 fltted in a cover plate 43 detachably secured to the housing by cap screws 44. The shaft 39 is formed with an integral cam 45 capableof oper- 3 ative engagement with theroller 30.

' Adjacent the gear 38,'there is a roller 46 roitatable on a shaft 41 carried by the housing 23, which roller is in operative engagement with the rack' [2 for preventing lateral movementthereof.

In the operation of the device if the throttle valve I8 is positioned as shown in Fig. 1, motive f fluid from the inlet port I! will flow into the upper end 0! the cylinder" through the passageway 2l, while the lower end of the cylinder is u vented to the atmosphere-through the passageway 22 and the throttle valve outlet 'porty2ll. From the upper end of the cylinder, the motive fluid will be admitted into the groove l5 via the ports [1, thereby exerting radial pressure on the d packing ring I 6 for assuming afluid tight joint I between the piston and the cylinder. The pistol; subjected to the'actionof the motive fluid admitted into the upper end of the cylinder, will be driven downwardly for affecting the working I stroke of,the rack l 2 and the consequential rotation of the gear 28 and the cam 45 in a counterclockwise direction in Fig. 1. Due to the action of the cam 45 on the roller 30, it will be understood that rotation of the cam in the above mentioned direction will cause the working stroke of the plunger 28 and tool 28 relative the tool for performing punching, shearing, riveting or like operations on the work placed therebetween.

In practice the cam 45 may be of any suitable shape calculated to impart slidable movement to the plunger 28 at any desired rate of speed. Preferably, the cam 45 is shaped substantially as shown in Fig. 1, whereby rotation of the cam resulting from the complete working stroke of the rack i2 will effect a materially shorter complete working stroke of the working plunger 28. In other words the cam 45 is preferably shaped to constitute with the gear 38 a speed reducing mechanism through which reciprocatory motion of the rack I2 is transmitted to the plunger 28 at a reduced rate of speed and consequently at an increased rate of power. For'instance where the device is used as riveting machine, the shape of the cam will be such that at the initial part oi its stroke the plunger 28 will move at a relatively high rate of speed, which rate will gradually decrease as the riveting operation proceeds so as to perform the work with a gradually increasing power.

Due to the engagement'of the roller 38 with the vertical guide 48, the lateral thrust normally resulting from the rotative engagement of the cam 42 with the roller 38 is exerted on the guide 44, thereby enabling free slidable movement of the plunger 28.

When the working operation is terminated, the throttle valve i8 may be rotated 180 for admitting motive fluid into the lower end of the cylinder through passageway 22, while the upper end of the cylinder is vented to the atmosphere via the passageway 2| and throttle valve outlet port 28. In this instance motive fluid acting under the piston i I will cause its return stroke for effecting the rotation of the gear 38 and consequently of the cam 45 in a clockwise direction in Fig. 1. During the return stroke of the piston il, while the cam rotates in a counterclockwise direction, the plunger 28 and the tool 29 will momentarily remain stationary. As the cam reaches the end of its rotation in the last mentioned direction, the step 85 formed on the rack i2 will engage the free end of the lever 83 for effecting pivotal movement thereof in a clockwise direction, resulting in the return stroke of the plunger 28 due to operative engagement of the cross shaft II with the lever 83.

While in the accompanying drawings and the foregoing specification there has been illustrated and described a somewhat specific form of the invention, such disclosure is for. illustrative purposes only and is not intended to limit the invention in any way.

I claim: I I

1. In a device of the character described, a housing, a work performing plunger reciprocable in said housing, a motor driven cam effecting the working strokes of said plunger at a rate of speed slower toward the ends of said strokes than at the beginning thereof, and intermittently motor driven means effecting the return strokes of said plunger at a substantially uniform rate of speed.

2. In a device of the character described, a motor driven oscillating cam, a reciprocable work performing plunger acted upon by said cam for effecting its working stroke during rotation of the cam in one direction, and motor driven means acting on said plunger for effecting the return stroke thereof during rotation of the cam in the other direction.

I 3. In a machine of the type described, a housing, a reciprocable work performing plunger, a power actuated cam, a roller between said cam and plunger acted upon by said cam for effecting the working strokes of said plunger, and guiding means engaged by said roller resisting lateral thrust of said plunger resulting from the action of said cam on said roller.

4. In a device of the character described, a housing, a plunger reciprocable relative to said housing, motor driven rotary means effecting the working strokes of said plunger, and swingable means motor driven in at least one direction for effecting the return strokes of said plunger.

5. In a device of the character described, a cam rotatable in two direction, a reciprocable work performing plunger, a roller between said cam and plunger acted upon by said cam during its rotation in one direction for effecting theworking stroke of said plunger, guiding means for said roller resisting lateral thrust of said plunger resulting from the action of said cam on the roller, and motor driven means effecting rotation of said cam in said one direction and effecting the return stroke of said plunger while rotating said cam in the other direction.

6. In a device of the characterdescribed, a power actuated reciprocatory member, a work performing plungerreciprocable parallely of said member, reciprocation transmitting means between said member and plunger including a cam active on said plunger for effecting the working stroke of said plunger at a gradually reducing rate of speed relative to that of said member, ar i means between said member and plunger acted upon by said member for effecting the return stroke of said plunger.

7. In a device of the character described, a power actuated reciprocatory member, a work performing plunger reciprocable parallelly of said member, a duality of longitudinal movement transmitting connections between said member and plunger one active during movement of said member in one direction for effecting the working stroke of said plunger at a gradually reducing rate of speed relative to said member and the other during movement of said member in the other direction for effecting return movement of said plunger.

8. In a device of the character described, a power actuated reciprocatory member, a reciprocable work performing plunger, means on said member operatively associated with means engaging said plunger for transmitting movement of said member in one direction to said plunger at a gradually reducing rateof speed relative to that of said member, and other means on said member operatively associated with means engageabie with said plunger for transmitting movement of said member in the other direction to said plunger.

PAUL VAN SIT'IERT. 

